1. Field of Invention
The present invention relates to a spindle motor for use as a rotational driving device for a hard disk or the like, and more particularly to a feeding construction for coils of a spindle motor.
2. Related art
A spindle motor for use as a rotational driving device (motor apparatus) for a recording disk such as a hard disk comprises a motor frame, a rotor supported via ball bearings or the like rotatably relative to the motor frame, a stator core held on the motor frame in such a manner as to confront a driving magnet of this rotor and coils wound around this stator core, and the rotor is used as a hub having a recording disk placed on an upper side thereof.
In the spindle motor constructed as described above, conventionally the motor frame is formed of a metal such as aluminum, and this motor frame is fixed to a chassis of a motor apparatus. Here, a flexible printed circuit board (hereinafter, referred to as an FPC board) or a connector is mounted on this motor frame on a side opposite (back side) to a side where the coils are disposed, and also a through-hole is formed in the motor frame for leading end portions of the coils therethrough out to the back side thereof. Thus, if the end portions of the coils are put through the through-hole so formed in the motor frame so as to be led to the back side thereof and are then electrically connected to an electrode portion of the FPC board or the connector, the coils can then be fed through this FPC board or the connector from the motor apparatus side.
In the conventional spindle motor, however, since the coils are constructed so as to be fed through a part such as the FPC board or the connector, there are caused such problems as below. In other words, in a case where a part such as the connector which is relatively thick in a height direction of the motor is fixed to a bottom portion of the motor frame, there is caused a problem that the motor is prevented from being thinned. In addition, there is a high possibility with a part such as the FPC board which protrudes to an exterior portion of the motor that it gets deformed or bent during a production process of the motor. If the FPC board is used, therefore, there are caused risks not only of a wiring pattern formed on the FPC board being disconnected but also of a terminal being deformed.
Moreover, with a notebook-sized personal computer, the more frequently it is carried by the user, the more it is subjected to a risk of being dropped, and therefore high impact resistance is required. If the conventional spindle motor is installed in the notebook-sized personal computer for driving a disk, however, there is caused a problem that the impact resistance required for the notebook-sized personal computer cannot be met due to a reason described below. Namely, as with the conventional spindle motor, if the aluminum motor frame is used, when the notebook-sized personal computer is dropped, an impact generated then is directly transmitted to the ball bearings via the motor frame and the ball bearings may thereby be deformed, and if this really happens, there are caused risks not only that noise and/or run-out is caused when the disk is rotated but also that the disk is prevented from being rotated.